1. FIELD
The present invention relates to titanium parts. More particularly, the invention relates to a system and method for making contoured net and near-net shape titanium parts for aircrafts and other applications.
2. RELATED ART
Titanium is frequently used for aircraft parts and other applications that are subjected to high stress and/or loads. Contoured titanium parts are commonly machined out of a large block of titanium, but this requires a large amount of material and complex machining equipment, such as a complex and expensive four or five-axis machine. Additionally, a block of titanium used to form the contoured part must be thick enough to allow machining the titanium part's contour. Much of the titanium block is machined away, resulting in a large percentage of wasted titanium.
Contoured titanium parts may also be formed by applying stress, pressure, or force to a sheet of titanium to curve or contour the titanium. However, this method is also problematic because titanium has a high yield strength, necessitating a large amount of force which produces residual stress in the titanium part. Additionally, the compressive strength of the die must be strong enough to cause the titanium to yield and to handle the force with which the die must be pressed into the titanium.
Another method of curving a sheet of titanium, called super plastic forming (SPF), involves heating the titanium to a temperature range which greatly reduces flow stresses of the titanium. However, SPF requires temperatures high enough to change the microstructure and resultant mechanical properties of the titanium. This change in microstructure properties are undesirable due to the affects it can have on the design and/or stress of the resulting titanium part.